Method of controlling phytopathogenic diseases on turfgrass

ABSTRACT

The present invention relates to a method of controlling dollar spot on turfgrass, in particular low to moderate disease pressure, using a fungicidally effective non-phytotoxic amount of (A) chlorothalonil and (B) acibenzolar-s-methyl.

The present invention relates to a method of controlling phytopathogenicdiseases on turfgrass. More specifically, the present invention relatesto a method of suppressing or controlling dollar spot on turfgrass witha combination of compounds comprising chlorothalonil andacibenzolar-s-methyl.

There are numerous problems that turfgrass managers face in maintainingturfgrass at a standard of quality expected by users. While the problemsare many, those relating to pests (including disease) are particularlychallenging to manage and control. Numerous types of pathogens, inparticular fungi, infect turfgrass plants on golf courses causing a lossof revenue from reduced playability. One example of a common problem forgolf course managers is a dollar spot infection caused by a fungalpathogen (Sclerotinia homoeocarpa). Dollar spot blights leaf tissues buttypically does not affect turfgrass roots or crowns and results in theformation of small, roughly circular, brown patches in grass growingareas.

Agricultural active chemicals for controlling pathogens, such asfungicides, are typically applied on golf courses as needed depending onthe extent of disease pressure, pathogen population, weather, and thelike. However, fungicide applications are highly controlled by coursebudget, availability of appropriate equipment, and availability ofqualified personnel for applying the agricultural active chemicals.

One known fungicide management tool useful for control of disease inturfgrass is chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile),which is a polychlorinated aromatic mainly used as a broad spectrum,non-systemic fungicide. Its structure can be represented as:

Chlorothalonil is an economical fungicide with broad-spectrum activity,providing partial to complete control of important turfgrass diseasessuch as dollar spot, brown patch, leaf spot/melting out, gray leaf spotand others and is considered to be at low risk for resistance due to itsmulti-site activity. Chlorothalonil is commercially available under thetrade name Daconil® (Syngenta Crop Protection, Inc.)

One of the reasons for chlorothalonil usage during turfgrass growingperiods is fungicide resistance management. For example, the a.i. can beused in programs with other fungicides that are at higher risk forresistance. Many of the resistance problems on golf courses haveoccurred due to the dollar spot organism. Chlorothalonil is an importantrotational partner in delaying such resistance and, once resistance hasoccurred, it is one of the most economical way of managing dollar spot.

One challenge occasioned by the use of chlorothalonil for diseasecontrol in turfgrass is that the product label sets restrictions andlimits on its annual maximum allowable application rate. Theserestrictions are set by regulatory authorities for environmental andproduct stewardship reasons. If not managed properly, the maximumallowable rate of chlorothalonil for greens, tees, and fairways can bereached before the end of a growing season. In some instances, it doesnot take long for the allotted amount of chlorothalonil to be used up. Aproblem arises when chlorothalonil rate limits are reached beforeturfgrass disease issues such as dollar spot are completely managed orcontrolled.

The compound acibenzolar-S-methyl (S-methylbenzo[1,2,3]thiadiazole-7-carbothioate) acts as a functional analogue ofthe natural signal molecule for systemic activated resistance (SAR),salicylic acid. It activates the host plant's natural defense mechanism.The structure of acibenzolar-S-methyl can be represented as follows:

Acibenzolar-S-methyl is commercially available under the trade nameActigard® (Syngenta Crop Protection, Inc.).

From Fry et al., Golf Course Management July 2006 it is suggested thatthe use of certain plant activators such as acibenzolar-S-methyl atrates of 6.1 grams/1,000 square meters may allow for reduction ofchlorothalonil rates on creeping bentgrass greens. However, it isreported by Fry that turf quality was below standard at the rates atwhich acibenzolar-S-methyl was applied.

Zhang et al., International Turfgrass Society Research Journal Volume10, 2005 discloses an evaluation of plant defense activators includingacibenzolar-S-methyl and/or β-aminobutyric acid in conjunction withchlorothalonil applied at a rate lower than currently recommended fordollar spot and brown patch control on creeping bentgrass puttinggreens. Again, Zhang et al. report turf quality was unacceptable at therates at which acibenzolar-S-methyl was applied.

High quality, healthy turf is essential, for example, to the golfingindustry. Accordingly, there is a continued need for alternative methodsto control dollar spot on turfgrass without undue phytotoxic effects andimproved turf quality. It would be particularly useful if such methodsand compositions utilized chlorothalonil in an amount at or below itsannual maximum allowable application rate.

In accordance with the present invention, it has now been discoveredthat the effectiveness of chlorothalonil in the suppression orcontrolling of dollar spot on turfgrass is enhanced when it is appliedat reduced rates in combination with a nonphytotoxic activity improvingamount acibenzolar-S-methyl. The level of turfgrass quality also isgreatly enhanced.

Accordingly, the present invention provides a method of suppressing orcontrolling dollar spot on turfgrass which comprises applying to theturfgrass, the locus thereof or the seeds thereof, a fungicidallyeffective non-phytotoxic amount of a combination of (A) chlorothaloniland (B) acibenzolar-s-methyl, wherein (A) is applied at a rate of from2,000 to 10,000 g/ha and (B) is applied at a rate of from 4 to 20 g/ha.

In one embodiment, the method of the invention is employed under eitherpre-disease conditions or under low to moderate dollar spot diseasepressure.

In another embodiment, the method of the invention is employed underconditions indicative of possible heavy disease pressure or under actualconditions of heavy disease pressure.

In accordance with the present invention, the method can be practicedwith a single application that, optionally, is repeated in suitableintervals as necessary to suppress or control dollar spot disease inturfgrass. Advantageously, in the practice of the methods of theinvention, the number of re-treatments or re-applications of thecombination of (A) and (B), is greater than the number of re-treatmentstypically possible with chlorothalonil solo formulations due to theenhanced chlorothalonil (A) activity which allows application at reducedrates, which enhanced activity is occasioned by the combination with (B)when applied at a rate of from 4 to 20 g/ha per application.

In addition, the amount of (B) suitable for enhancing the activity of(A) not only is nonphytotoxic to the turfgrass, it also further improvesthe quality of the turfgrass to which it is applied. Accordingly, themethod of the invention is useful both to (1) manage dollar spot diseaseby suppressing or controlling the dollar spot microorganisms and (2)enhance the quality of the turfgrass to which it is applied. The methodof the invention enhances the ability of end-users such as lawn careoperators, golf course technicians and the like to manage, suppress orcontrol turfgrass dollar spot disease issues with chlorothalonilformulations without reaching chlorothalonil application rate limits.

The method according to the invention also is suitable to improve thequality of turfgrass. Therefore, in another aspect of the presentinvention, a method to improve the quality of turfgrass is provided,which comprises applying to the turfgrass, the locus thereof or seedsthereof a turf quality enhancing, non-phytotoxic amount of a combinationof (A) chlorothalonil and (B) acibenzolar-s-methyl.

As noted above, in one embodiment, in the practice of the methods of theinvention, chlorothalonil (A) is applied at a rate of from 2,000 to10,000 g/ha and acibenzolar-S-methyl (B) is applied at a rate of from 4to 20 g/ha.

In one embodiment, the method of suppressing or controlling dollar spotand the method to improve the quality of turfgrass comprises applicationto the turfgrass, the locus thereof or seeds thereof of a combination of(A) and (B) in a weight ratio of from 300:1 to 600:1.

In another embodiment, the method of suppressing or controlling dollarspot comprises application to the turfgrass, the locus thereof or seedsthereof of a fungicidally effective non-phytotoxic amount of acombination of (A) and (B) either pre-disease, or under low to moderatedollar spot disease pressure.

In another embodiment, the method of suppressing or controlling dollarspot, or the method to improve the quality of turfgrass comprises atreatment regime, where the combination of (A) and (B) at the foregoingrates and ratios is re-applied to the turfgrass or to the locus thereofat intervals of from 5 to 25 days, up to the cumulative maximum labeledrate for chlorothalonil per turf growing season for the specificturfgrass locus being treated according to existing restrictions. Forexample, in one embodiment, chlorothalonil is applied up to a cumulativemaximum application rate of 100 kg/ha per turf growing season.

In a more specific embodiment, in the practice of the methods of theinvention, the combination of (A) and (B) is re-applied to the turfgrassor the locus thereof at intervals of from 7 to 21 days; morespecifically, from 7 to 14 days, up to the cumulative maximum labeledrate for chlorothalonil for the turfgrass locus being treated.

Specific turfgrass loci suitable for the methods of the inventioninclude those listed on the current product label for Daconil Action™which is incorporated by reference herein. For example, suitableturfgrasses include sod farms; turf on golf courses such as roughs,fairways, tees and greens; professional and collegiate athletic fields;and lawns around commercial and industrial buildings.

In another aspect of the methods of the invention, one or both of (A)and (B) can be applied to the turfgrass or the locus thereof usingturfgrass seed as a carrier.

In a further aspect, the method of suppressing or controlling dollarspot comprises applying to the turfgrass, the locus thereof or seedsthereof a fungicidally effective non-phytotoxic amount of a compositioncomprising a mixture of (A) chlorothalonil and (B) acibenzolar-s-methyl.

In a further aspect, the method to improve the quality of turfgrasscomprises applying to the turfgrass, the locus thereof or seeds thereofa turf quality enhancing non-phytotoxic amount of a compositioncomprising a mixture of (A) chlorothalonil and (B) acibenzolar-s-methyl.

Compositions comprising mixtures of (A) and (B) used in the methods ofthe present invention can be tank mixtures or premixes wherein thecomposition may further comprise adjuvants, solvents, carriers,surfactants or extenders.

As used herein the phrase “quality” of turfgrass is meant to includevisual quality of turfgrass and functional quality of turfgrass.

“Visual quality” of turfgrass relates to the visual appearance, such asdensity (the number of aerial shoots per unit area), uniformity (forexample uniformity of texture, e.g. width of the leaf blades, which canbe fine-textured as for example in red fescue or coarse-textured as forexample in tall fescue), colour or smoothness (which affects for examplethe playability of a golf course).

“Functional quality” of turfgrass relates to, for example, rigidity(resistance of the turfgrass leaves to compression and is related to thewear resistance of a turf), elasticity (tendency of the turfgrass leavesto spring back once a compressing force is removed), resiliency(capacity of a turf to absorb a shock without altering its surfacecharacteristics), ball roll (average distance a ball travels upon beingreleased to a turf surface), yield (measure of clippings removed withmowing), verdure (measure of amount of aerial shoots remaining aftermowing), rooting (amount of root growth evident at any one time duringthe growing season) and recuperative capacity (capacity of turfgrassesto recover from damage caused by disease organism, insects, traffic andthe like).

An improvement in the quality of turfgrass can relate to one of thementioned visual or functional quality characteristics or to anycombination of these quality characteristics.

According to the present invention, an “improvement” is a measurable ornoticeable increase in a given turfgrass quality characteristic over thesame turfgrass quality characteristic produced under the sameconditions, but without the application of the subject method.

An improvement in the quality characteristics of turfgrass is, forexample, a greener or more pleasant, leaf colour of the turf.

According to the invention, by “turfgrass” there is understood an annualor perennial Gramineae. Said gramineae preferably belongs to one or moreof the genera Agropyron, Agrostis, Axonopus, Bromus, Buchloë, Cynodon,Eremochloa, Festuca, Lolium, Paspulum, Pennisetum, Phleum, Poa,Stenotaphrum or Zoysia. More preferably, said gramineae belongs to oneor more of the genera Agrostis, Buchloë, Cynodon, Eremochloa, Festuca,Lolium, Paspulum, Pennisetum, Poa, Stenotaphrum or Zoysia.

According to the invention by “turf” is understood as a group ofturfgrass, which covers a surface area of ground and is subject toregular maintenance.

The present invention can be practiced with all turfgrasses, includingcool season turfgrass and warm season turfgrass.

Examples of cool season turfgrasses are: Bluegrasses (Poa L.), such asKentucky Bluegrass (Poa pratensis L.), Rough Bluegrass (Poa trivialisL.), Canada Bluegrass (Poa compressa L.) and Annual Bluegrass (Poa annuaL.); Bentgrasses (Agrostis L.), such as Creeping Bentgrass (Agrostispalustris Huds.), Colonial Bentgrass (Agrostis tenius Sibth.), VelvetBentgrass (Agrostis canina L.) and Redtop (Agrostis alba L.); Fescues(Festuca L.), such as Creeping Red Fescue (Festuca rubra L.), ChewingsFescue (Festuca rubra var. commutata Gaud.), Sheep Fescue (Festuca ovinaL.), Hard Fescue (Festuca longifolia), Tall Fescue (Festuca arundinaceaSchreb.), Meadow Fescue (Festuca elatior L.); Ryegrasses (Lolium L.),such as Perennial Ryegrass (Lolium perenne L.), Annual (Italian)Ryegrass (Lolium multiflorum Lam.); Wheatgrasses (Agropyron Gaertn.),such as Fairway Wheatgrass (Agropyron cristatum (L.) Gaertn.), WesternWheatgrass (Agropyron smithii Rydb.). Other cool season turfgrassesinclude Smooth Brome (Bromus inermis Leyss.) and Timothy (Phleum L.).

Examples of warm season turfgrasses are Bermudagrasses (Cynodon L. C.Rich), Zoysiagrasses (Zoysia Willd.), St. Augustinegrass (Stenotaphrumsecundatum (Walt.) Kuntze), Centipedegrass (Eremochloa ophiuroides(Munro.) Hack.), Carpetgrass (Axonopus Beauv.), Bahiagrass (Paspalumnotatum Flugge.), Kikuyugrass (Pennisetum clandestinum Hochst. exChiov.), Buffalograss (Buchloe dactyloides (Nutt.) Engelm.) and Seashorepaspalum (Paspalum vaginatum swartz).

The method according to the present invention is effective to suppressor control turfgrass against incidence of dollar spot.

The method according to the invention is particularly effective tosuppress or control turfgrass against developing dollar spot occasionedby Sclerotinia homeocarpa, Lanzia or Moillerodiscus spp. eitherpre-disease or under low to moderate disease pressure, such as whenconditions are becoming favorable for disease or disease has just beendetected.

In one embodiment, low disease pressure indicates a level of disease offrom 0 to 10%; and moderate disease pressure indicates a level ofdisease of from 10 to 20% incidence of dollar spot disease (for example,a percentage calculated based on the number of dollar spot infectioncenters per unit area of the turfgrass being treated). In anotherembodiment, pre-disease or low to moderate disease pressure means thatenvironmental conditions are not ideal for a full blown epidemic leadingto heavy disease pressure.

In another embodiment, heavy disease pressure means that environmentalconditions are ideal for a full blown epidemic leading to heavy diseasepressure in check plots (21-100%). The methods of the invention aresuitable to suppress or control disease under such conditions prior todisease development or when disease has just been detected.

The method according to the invention is particularly effective tosuppress or control turfgrass against Sclerotinia homeocarpa.

The method according to the invention is particularly effective tosuppress or control turfgrass against Lanzia spp.

The method according to the invention is particularly effective tosuppress or control turfgrass against Moillerodiscus spp.

The term “locus” of turfgrass as used herein is intended to embrace theplace on which the turfgrass are growing, the place where the seeds ofthe turfgrass are sown or the place where the seeds of the turfgrasswill be placed for subsequent plant growth. According to the invention,the “locus” of a turf can relate to soil or to a substrate. An examplefor such a locus is a golf course, on which turfgrass is managed.

According to the invention the term “soil” means natural soil, which istypically present on a land area, such as soil being present on a golfcourse, or means soil, that has been modified, such as soil beinggranulated and/or treated with agrochemicals, such as for examplefertilizers. An example of granulated and/or treated soil is disclosedin U.S. Pat. No. 5,265,372.

According to the invention the term “substrate” means a medium for thegrowth of turfgrass and the like, suited for application to a variety ofexisting ground structures. Typically, such mediums are soil-freemixtures that include sufficient proportions of ingredients ofelastomeric granules, suitable binding emulsion, mineral aggregate,filler and controlled release plant nutrient particles, so that whenlaid and cured, said mixture produces a water permeable, resilientsubstrate having air pockets through which a root system of turfgrasscan penetrate. Turfgrass growing on said substrate can form a turf,which can be applied to non-porous surfaces, such as for example roofsof buildings, terraces and other hard surface areas, or to poroussurfaces, such as for example football fields or golf courses. Examplesof such substrates are described in WO 2005/002323. Elastomeric granulescan be, for example, granules of rubber, granules of recycled vehicletyre rubber or mixtures thereof.

According to the invention the term “applied” means eithersimultaneously or sequentially. More specifically, in the practice ofthe method, the compounds (A) and (B) of the invention may be appliedeither simultaneously or sequentially. If administered sequentially, thecomponents may be administered in any order in a suitable timescale, forexample, with no longer than 24 hours between the time of administeringthe first component and the time of administering the last component.Suitably, all the components are administered within a timescale of afew hours, such as one hour. If the components are administeredsimultaneously, they may be administered separately or as a tank mix oras a pre-formulated mixture of all the components or as a pre-formulatedmixture of some of the components tank mixed with the remainingcomponents.

In accordance with the method of the present invention, the compounds(A) and (B) are applied to the turfgrass by treating the turfgrass, thelocus thereof or seeds thereof.

Fungicidal compositions used in the method of the invention can beprepared on site by the end-user shortly before application to theturfgrass, the locus thereof or seeds thereof by mixing in aqueoussolution a chlorothalonil containing composition, anacibenzolar-S-methyl containing composition and, optionally, a suitablesurfactant or adjuvant. Such compositions are typically referred to as“tank-mix” compositions.

Alternatively, the compositions used in the method of the invention maybe provided to the end-user already formulated, either at the desireddilution for application (“ready to use” compositions) or requiringdilution, dispersion, or dissolution in water by the end-user(“concentrate” compositions). Such preformulated concentrates can beliquids or particulate solids.

Water application volumes for applying the combination of (A)+(B) inaccordance with the method range from 500 to 1000 liters per hectare.

The amount of compounds (A) and (B) to be applied in the practice of amethod according to the invention will depend on various factors, suchas the subject of the treatment, such as, plants, turfgrass locus orseeds; the type of treatment, such as, for example spraying, spreadingor seed dressing; the purpose of the treatment, such as, for examplesuppression or control dollar spot; the type of dollar spot fungi to becontrolled; enhancing turf quality, the application time; environmentalconditions, the number of re-treatment intervals desired or theturfgrass species.

In one embodiment of the invention, the methods according to theinvention are carried out by applying or treating the turfgrass, thelocus thereof or the seeds thereof with a fungicidally effectivenon-phytotoxic amount of a composition comprising a mixture of (A) and(B) according to the invention.

In another embodiment of the invention, the methods according to theinvention are carried out by applying or treating the turfgrass, thelocus thereof or seeds thereof with a fungicidally effectivenon-phytotoxic amount of a combination of (A) and (B) according to theinvention.

In yet another embodiment of the invention, the methods according to theinvention are carried out by applying or treating the turfgrass, thelocus thereof or seeds thereof with a turf quality enhancingnon-phytotoxic amount of a combination comprising (A) and (B), eitherpre-disease or under low to moderate disease pressure, where thechlorothalonil (A) is applied at a rate of from 2,000 to 10,000 g/ha andacibenzolar-S-methyl (B) is applied at a rate of from 4 to 20 g/ha.

Application to Turfgrass:

The methods according to the invention can be practiced by treating theturfgrass with a combination comprising an effective amount of (A) and(B) according to the invention. Within said embodiment of the invention,the combination containing (A) and (B) is suitably applied to theturfgrass by spraying or spreading. Treatment of turfgrass in accordancewith the methods of the invention may be performed by lawn careoperators or golf course technicians.

In one embodiment of the inventive methods, to maintain high quality,healthy turfgrass on the intended surface area of ground, such as forexample, a golf course, a sports field, a park area or a home lawn, andto protect said turfgrass against dollar spot diseases, combinationscomprising (A) and (B) are applied to the turfgrass once or more thanonce during maintenance of the turfgrass.

Suitably, the methods of the invention are practiced by application of acombination comprising (A) and (B) once or more than once during agrowing season of the turfgrass, in particular, at intervals of from 5to 21 days, more particularly, at intervals of from 7 to 14 days, eitherpre-disease or under low to moderate dollar spot disease pressure. Inone embodiment, the methods of the invention comprise from 6 to 8applications of a combination of (A) and (B) at intervals of from 7 to14 days.

Advantageously, in the practice of the method of suppressing orcontrolling dollar spot according to the invention it is possible toinhibit or destroy the dollar spot pathogens which occur on turfgrass,while at the same time the parts of turfgrass which grow later are alsoprotected from attack by dollar spot pathogens.

In accordance with the method of the invention for dollar spotsuppression or control, the combination of (A) and (B) is applied beforedisease or after low to moderate infection of the turfgrass by the fungiwhich cause dollar spot.

When applied to the turfgrass for suppression or control of dollar spot,chlorothalonil (A) is typically applied at a rate of from 2000 to 10,000g/ha; from 3000 to 10000 g/ha; suitably from 3000 to 8000 g/ha, alsosuitably from 3000 to 5000 g/ha.

When applied to the turfgrass for enhancing suppression or control ofdollar spot, acibenzolar-S-methyl (B) is typically applied at a rate offrom 4 to 20 g/ha; from 5 to 16 g/ha (greens, for example); suitablyfrom 5 to 12 g/ha (fairways, for example); also suitably from 7 to 10g/ha (fairway, for example).

As noted, compositions used in the method of the invention comprisechlorothalonil and acibenzolar-S-methyl in an activity improving amount.In the compositions used in the method of this invention, the weightratio of chlorothalonil to acibenzolar-S-methyl at which the fungicidaleffect is improved lies within the range of between about 300:1 andabout 600:1. Suitably, the weight ratio of chlorothalonil toacibenzolar-S-methyl is about 500:1

In another aspect, suppression or control of dollar spot is achieved byre-applying a fungicidally non-phytotoxic amount of the combination of(A):(B), suitably at the foregoing rates and weight ratios, at intervalsof from 5 to 21 days, suitably from 7 to 14 days, during the turfgrowing season.

In a particular embodiment, 6 to 8 applications of a combination (A)+(B)is applied at 14 day intervals, pre-disease or under low to moderatedisease pressure during the turf growing season.

Application to the Locus of the Turfgrass:

The compositions used in the method according to the invention can beapplied to the turfgrass by treating the locus of the turfgrass with acomposition comprising (A) and (B) according to the invention.

Application of compositions used in the method of the invention to alocus covers liquid (sprayable) or granular (active ingredient (a.i.) oninert and a.i. on fertilizer) (spreadable) applications as well.

For example, in the practice of method of the invention compositionscomprising (A) and (B) can be applied to the soil before or after theseeds of the turfgrass are sown or placed into the soil; or suchcompositions are applied according to the method of invention to asubstrate for the growth of turfgrass before or after the seeds of theturfgrass are placed into the substrate; or the compositions appliedaccording to the method of the invention can be applied to the soilbefore turfgrass grown on a substrate are placed on top of the soiltogether with the substrate.

In one embodiment, according to the method of the invention compositionscomprising (A) and (B) are applied to the turfgrass as a sprayableliquid formulation. In another embodiment, such compositions are appliedto the turfgrass as a granular formulation. Suitable granules includeinert and fertilizer granules. The active ingredient may be dispersedthroughout, impregnated into, or coated on the surface of the granules.

Application to the Seeds of the Turfgrass:

The method according to the invention also can be practiced by applyingthe compositions containing (A) and (B) to the seeds of the turfgrass bytreating the seeds with such a composition. When the method according tothe invention involves using combinations of (A) and/or (B) for treatingseed, rates of 0.001 to 50 g of the compound mixture per kg of seed,suitably from 0.01 to 10 g per kg of seed, are generally sufficient. Inone embodiment, an amount of seed used as a carrier for (A) and/or (B)can be applied to the soil or substrate to deliver a suitable amount ofthe active ingredients.

The compositions used in the methods of the invention may be employed inany conventional form, for example in the form of a twin pack, a powderfor dry seed treatment (DS), an emulsion for seed treatment (ES), aflowable concentrate for seed treatment (FS), a solution for seedtreatment (LS), a water dispersible powder for seed treatment (WS), acapsule suspension for seed treatment (CF), a gel for seed treatment(GF), an emulsion concentrate (EC), a suspension concentrate (SC), asuspo-emulsion (SE), a capsule suspension (CS), a water dispersiblegranule (WG), an emulsifiable granule (EG), an emulsion, water in oil(EO), an emulsion, oil in water (EW), a micro-emulsion (ME), an oildispersion (OD), an oil miscible flowable (OF), an oil miscible liquid(OL), a soluble concentrate (SL), an ultra-low volume suspension (SU),an ultra-low volume liquid (UL), a technical concentrate (TK), adispersible concentrate (DC), a wettable powder (WP) or any technicallyfeasible formulation in combination with agriculturally acceptableadjuvants.

Said compositions used according to the methods of invention may beproduced in conventional manner, e.g. by mixing the compounds (A) and/or(B) with at least one appropriate formulation adjuvant.

The term “formulation adjuvant” according to the invention denotes anatural or synthetic, organic or inorganic material with which thecompounds (A) and (B) are combined in order to facilitate itsapplication to turf. This adjuvant is hence generally inert, and it mustbe agriculturally acceptable, in particular to turf.

The formulation adjuvant can be a carrier or a surfactant. Incompositions according to the invention more than one adjuvant can bepresent, in such embodiments more than one carrier and/or more than onesurfactant can be present, a non-limiting example would be one carrierand two surfactants.

The “carrier” can be a liquid carrier (water, alcohols, ketones,petroleum fractions, aromatic or paraffinic hydrocarbons, chlorinatedhydrocarbons, liquefied gases, and the like) or a solid carrier.

Suitable liquid carriers are, but are not restricted to: aromatichydrocarbons, in particular the fractions C₈ to C₁₂, such as xylenemixtures or substituted naphthalenes, phthalic esters such as dibutyl ordioctyl phthalate, dipropylene glycol dibenzoate, aliphatic hydrocarbonssuch as cyclohexane or paraffins, alcohols and glycols as well as theirethers, esters and diesters, such as ethylene glycol monomethyl ether,ketones such as cyclohexanone, strongly polar solvents such as, but notrestricted to, N-methyl-2-pyrrolidone, dimethyl sulfoxide ordimethylformamide, and, if appropriate, epoxidized vegetable oils orsoybean oil; or water.

Suitable solid carriers are, but are not restricted to: aluminiumsilicate, urea, sodium sulphate, talc, calcium sulphate or potassiumsulphate and seed.

According to the invention a single carrier or a mixture of two or morecarriers may be present in the composition(s) used in the methodsaccording to the invention.

“Surfactants” are non-ionic, cationic, amphoteric and/or anionicsurfactants having good emulsifying, dispersing and wetting properties.According to the invention a single surfactant or a mixture of two ormore surfactants may be present. The surfactants customarily employed informulation technology are described, inter alia, in the followingpublications: “McCutcheon's Detergents and Emulsifiers Annual”, MCPublishing Corp., Glen Rock, N.J., 1988 and M. and J. Ash, “Encyclopediaof Surfactants”, Vol. I-III, Chemical Publishing Co., New York,1980-1981.

Among the surfactants there may be mentioned, e.g., polyacrylic acidsalts, lignosulphonic acid salts, phenolsulphonic or (mono- ordi-alkyl)naphthalenesulphonic acid salts, laurylsulfate salts,polycondensates of ethylene oxide with lignosulphonic acid salts,polycondensates of ethylene oxide with fatty alcohols or with fattyacids or with fatty amines, substituted phenols (in particularalkylphenols or arylphenols such as mono- and di-(polyoxyalkylenealkylphenol) phosphates, polyoxyalkylene alkylphenol carboxylates orpolyoxyalkylene alkylphenol sulfates), salts of sulphosuccinic acidesters, taurine derivatives (in particular alkyltaurides),polycondensates of ethylene oxide with phosphated tristyrylphenols andpolycondensates of ethylene oxide with phosphoric esters of alcohols orphenols.

A seed dressing formulation is applied in a manner known per se to theseeds employing the compositions according to the invention and adiluent in suitable seed dressing formulation form, e.g. as an aqueoussuspension or in a dry powder form having good adherence to the seeds.Such seed dressing formulations are known in the art. Seed dressingformulations may contain the active ingredients in encapsulated form,e.g. as controlled release capsules or microcapsules.

The compositions used in the methods according to the invention maycomprise one or more formulation additives, such as, but not limited to,biocides, anti-freeze, stickers, thickeners and compounds that provideadjuvancy effects including, for example, one or more phthalocyanines orcopper phthalocyanines including pigment green such as pigment green 7;phthalocyanine green g; or pigment green 42.

In general, when phthalocyanines or copper phthalocyanines are presentin compositions used in the methods according to the invention, the rateof application to the turfgrass or to the locus of the turfgrass is from0.001 to 10 kilograms of phthalocyanine per hectare (kg/ha), suitablyfrom about 0.01 to about 2 kg/ha, more suitably from about 0.1 to about1 kg/ha, most suitably from about 0.2 to about 0.8 kg/ha.

The compositions used in the methods according to the invention maycomprise one or more additional active ingredients, such as a fungicide,insecticide, herbicide or growth regulator. An example would be acomposition that comprises another fungicide. Any suitable fungicide orherbicide may be used in the composition, for example to provide controlof a broader spectrum of pests, to overcome problems and delay the onsetof resistance, or to provide improved efficacy though an additive orsynergistic effect of the active ingredients. Turf wetting agents mayalso be used in conjunction with the method of the invention. Suitableexamples include Revolution® or Radiance® (Aquatrols); and Qualibra™(Syngenta).

In one embodiment, the methods of the invention for suppressing orcontrolling dollar spot on turfgrass as specified herein contemplate oneor more additional active ingredients being applied selected from thelist comprising azoxystrobin; trinexapac-ethyl; paclobutrazole;neonicotinoids such as thiamethoxam and imidacloprid; bisamides such ascyantraniliprole and chlorantraniliprole; fluazinam; propiconazole,difenoconazole, cypraconazole; fludioxonil; mefenoxam; cyprodinil;thiophanate methyl; iprodione; triadimefon; propamocarb; fosetyl-al;flurprimidol; flutalonil; pyraclostrobin; boscalid; vinclozolin;trifloxystrobin; myclobutanil; fenarimol; SDHI fungicides such asisopyrazam and solatenol; fluoxastrobin; phophonic acid derivatives suchas phosphonic acid, monopotassium salt; abamectin; cis-jasmone;abamectin iron chelate mixtures; and lambda cyhalothrin.

In another embodiment, the methods of the invention contemplate afungicidally effective non-phytotoxic amount of a composition comprisinga mixture of chlorothalonil and ASM as noted above along with fungicideshaving protectant modes of fungicidal action being applied to theturfgrass or to the locus of the turfgrass. Suitable fungicides withprotectant modes of action include fluazinam and mancozeb.

The practice of the methods of the invention also contemplateapplication of a fungicidally effective non-phytotoxic amount of acomposition comprising a mixture of chlorothalonil and ASM as notedabove along with fungicides having post infection modes of fungicidalaction to the turfgrass or to the locus of the turfgrass. Suitablefungicides with post-infection modes of action include

-   -   Triazoles including propiconazole, difenoconazole,        cyproconazole, triticonazole, metconazole, triadimefon and        tebuconazole    -   Strobilurins including azoxystrobin trifloxystrobin,        fluoxastrobin and pyraclostrobin    -   Fludioxonil    -   Thiabendazole,    -   SDHIs including—boscalid, fluopyram, isopyrazam, penthiopyrad,        solatenol    -   Phenylamide including metalaxyl and mefonoxam.

The practice of the methods of the invention further contemplateapplication of a fungicidally effective non-phytotoxic amount of acomposition comprising a mixture of chlorothalonil and ASM as notedabove along with plant growth regulators (PGR). Suitable plant growthregulators for use in the inventive method include azole PGR chemistry(such as uniconazole, and paclobutrazol), cyclohexane carboxylates (suchas trinexapac-ethyl, and prohexadione-calcium), pyrimidinyl carbinols(such as flurprimidol, and ancymidol), quarternary ammoniums (such aschlormequat-chloride, and mepiquat-chloride), and sulphonyl-aminophenyl-acetamides (such as mefluidide). Plant growth regulators such astrinexapac-ethyl are suitable for use in the practice of the method ofthe invention to improve turf colour, quality, reduce clippings andimprove rooting.

In general, the compositions according to the invention include from0.01 to 90% by weight of compounds (A)+(B), from 0 to 20% surfactant andfrom 10 to 99.99% carrier.

Concentrated forms of compositions used in the methods according to theinvention generally contain in between about 2 and 80%, preferablybetween about 5 and 70% by weight of (A)+(B). Application forms offormulation may for example contain from 0.01 to 20% by weight,preferably from 0.01 to 5% by weight of a compound of chlorothalonil.Whereas commercial products will preferably be formulated asconcentrates, the end user will normally employ diluted formulations.

The compounds (A) chlorothalonil and (B) acibenzolar-s-methyl arecommercially available.

In a one embodiment of the present invention, compositions suitable foruse in the methods according to the invention comprise 53.94%chlorothalonil, 0.11% acibenzolar-S-methyl and 45.95% inert ingredients,such as a composition sold under the designation Daconil Action™(Syngenta)

The Examples which follow serve to illustrate the invention, “activeingredient” denoting a compounds (A)+(B)

FORMULATION EXAMPLE

Suspension concentrate Active ingredients 40% Propylene glycol 10%Nonylphenol polyethylene glycol ether  6% (15 mol of ethylene oxide)Sodium lignosulfonate 10% Carboxymethylcellulose  1% Silicone oil (inthe form of a 75% emulsion in water)  1% Water 32%

In preparing and SC, the finely ground active ingredients are mixed withthe adjuvants, giving a suspension concentrate from which suspensions ofany desired dilution can be obtained by dilution with water. Using suchdilutions, living plants as well as plant propagation material can betreated and protected against infestation by microorganisms, byspraying, pouring or immersion.

The following examples are for illustrative purposes only. The examplesare not intended as necessarily representative of the overall testingperformed and are not intended to limit the invention in any way.

BIOLOGICAL EXAMPLES

Enhanced control of turf dollar spot (Sclerotinia homoeocarpa) whenacibenzolar-S-methyl is applied in combination with chlorothalonil isclaimed. Control of turf dollar spot (Sclerotinia homoeocarpa) withreduced rates of acibenzolar-S-methyl plus chlorothalonil is alsoclaimed.

Example 1. Disease Control

Daconil Action (54% chlorothalonil and 0.176% acibenzolar-S-methyl) andQuali-Pro Chlorothalonil 720 were applied at golf course fairwayrecommended rates of 2 fluid ounces per 1000 square feet of turf andreduced rates of 1.82, 1.59 and 1.3 fluid ounces per 1000 square feet ofturf. These rates are equivalent to the following:

TABLE 1 Rate-fluid acibenzolar- ounces/1000 Chlorothalonil S-methylTreatment sq. ft. g ai/ha g ai/ha Daconil Action 2.0 4600 9.2 DaconilAction 1.82 4160 8.3 Daconil Action 1.59 3640 7.3 Daconil Action 1.32980 6.0 Quali-Pro 2.0 4600 Chlorothalonil 720 Quali-Pro 1.82 4160Chlorothalonil 720 Quali-Pro 1.59 3640 Chlorothalonil 720 Quali-Pro 1.32980 Chlorothalonil 720

Trials were conducted on creeping bentgrass (Agrostis stolonifera) andarranged in randomized complete block designs with four replications.Treatments were applied on a 14 day schedule. Typically 6 applicationswere applied per trial. Percent turf area exhibiting dollar spotsymptoms were assessed throughout the trial period. Turf quality wasalso evaluated.

Dollar spot developed to significantly damaging levels at all locations.In Table 2, average number of dollar spot loci across ratings isprovided within and across trials 1-5. In Table 3, percent dollar spotcontrol is provided within and across trials 1-5. In Table 4, averagenumber of dollar spot loci across ratings is provided within and acrosstrials 6-8. In Table 5, percent dollar spot control is provided withinand across trials 6-8.

All rates of Daconil Action (2.0, 1.82, 1.59, and 1.3 fluid ounces) wereequal to or superior to the 2 oz rate of Quali-Pro Chlorothalonil 720.This includes the recommended label rate of 2.0 fluid ounces as well asreduced rates of 1.82, 1.59 and 1.3 fluid ounces. The 1.3 ounce rate ofDaconil Action was numerically equal to the 2.0 and 1.82 fluid ouncerate of Quali-Pro Chlorothalonil 720 and significantly (P=0.10) superiorto the 1.59 and 1.3 fluid ounce rates.

These data support the claim that Daconil Action (acibenzolar-S-methylplus chlorothalonil) provides enhanced control of turf dollar spot(Sclerotinia homoeocarpa) over chlorothalonil applied alone. Applyingacibenzolar-S-methyl in combination with chlorothalonil may allow for asmuch as a 30% rate reduction without loss of disease control.

Daconil Action is a unique blend of a multiple-site contact fungicide(chlorothalonil) with acibenzolar-S-methyl a systemic compound used forcontrol of disease through induction of host plant resistance. The modeof action of acibenzolar-S-methyl mimics the natural systemic activatedresistance (SAR) response found in most plant species. This SAR responsedoes not involve direct activity against the target pathogens but relieson the plants natural defense mechanism.

TABLE 2 Average counts of dollar spot loci across all ratings dateswithin and across all trials 1-5. Total Dollar Spot Counts oz/ TrialTrial Trial Trial Trial 1000 1 2 3 4 5 sq. ft. PA* CT* MI* WI* NJ* AVG**1 Untreated 124.1 114.3 235.3 220 476.4 234.0 Check 2 Daconil 2.0 14.8840.6 31 106.7 64.9 51.6 Action 3 Daconil 1.82 22.53 34.9 36.2 83.6 61.947.8 Action 4 Daconil 1.59 6.8 47.6 58.5 110.2 101.4 64.9 Action 5Daconil 1.3 23.3 52.6 91.3 124.2 112.6 80.8 Action 6 Quali-Pro 2.0 36.750.2 74.9 121.1 106 77.8 Chlorothalonil 7 Quali-Pro 1.82 15.9 104.8 76.2122.4 122.1 88.3 Chlorothalonil 8 Quali-Pro 1.59 58.7 41.6 131.9 195.4124.5 110.4 Chlorothalonil 9 Quali-Pro 1.3 33.68 86.6 129.5 260.7 145.6131.2 Chlorothalonil *Average number of dollar spot loci or infectionsacross all rating dates within trials. **Average number of dollar spotloci or infections across all rating dates and locations.

TABLE 3 Percent dollar spot control across all ratings within and acrossall trials 1-5. % Control Trial Trial Trial Trial Trial oz/1000 1 2 3 45 Treatment sq. ft. PA* CT* MI* WI* NJ* AVG** 1 Untreated 0 0 0 0 0  0.0Check 2 Daconil 2.0 88 64 87 52 86 75.4 Action abc*** 3 Daconil 1.82 8269 85 62 87 77.0ab Action 4 Daconil 1.59 95 58 75 50 79 71.3a-d Action 5Daconil 1.3 81 54 61 44 76 63.3de Action 6 Quali-Pro 2.0 70 56 68 45 7863.5cde Chlorothalonil 7 Quali-Pro 1.82 87 8 68 44 74 56.4efChlorothalonil 8 Quali-Pro 1.59 53 64 44 11 74 49.1fg Chlorothalonil 9Quali-Pro 1.3 73 24 45 −19 69 38.6g Chlorothalonil *Average percentcontrol of dollar spot across all rating dates within trials. **Averagepercent control dollar spot across all rating dates and locations.***Means with same letter not different, LSD (P = 0.10)

TABLE 4 Average counts of dollar spot loci across all ratings dateswithin and across all trials 6-8. Total Dollar Spot Counts oz/1000 Trial6 Trial 7 Trial 8 sq. ft. IN* CT* WI* AVG* 1 Untreated Check 9.95 115.6732.03 52.6 2 Daconil Action 2.0 1.49 11.66 19.81 11.0 3 Daconil Action1.82 1.26 9.4 17.01 9.2 4 Daconil Action 1.59 1.72 15.69 15.85 11.1 5Daconil Action 1.3 2.10 31.81 20.58 18.2 6 Quali-Pro Chlorothalonil 2.02.31 28.4 30.01 20.2 7 Quali-Pro Chlorothalonil 1.82 1.79 20.95 16.6513.1 8 Quali-Pro Chlorothalonil 1.59 2.96 22.94 20.71 15.5 9 Quali-ProChlorothalonil 1.3 2.25 44.29 19.34 22.0 *Average number of dollar spotloci or infections across all rating dates within trials. **Averagenumber of dollar spot loci or infections across all rating dates andlocations.

TABLE 5 Percent dollar spot control across all ratings within and acrossall trials 6-8. % Control oz/ Trial Trial Trial 1000 6 7 8 Treatment sq.ft. IN CT WI AVG 1 Untreated Check (9.95) (115.67) (32.03) (52.6) 2Daconil Action 2.0  85.0 89.9 38.15 79 3 Daconil Action 1.82 87.3 91.8746.89 82.5 4 Daconil Action 1.59 82.7 86.4 50.15 78.9 5 Daconil Action1.3  78.89 72.49 35.74 65.39 6 Quali-Pro Chlorothalonil 2.0  76.7 75.46.30 61.5 7 Quali-Pro Chlorothalonil 1.82 82.0 81.8 48.01 75.0 8Quali-Pro Chlorothalonil 1.59 70.2 80.16 35.34 70.5 9 Quali-ProChlorothalonil 1.3  77.3 61.7 39.61 58.1 *Average percent control ofdollar spot across all rating dates within trials. **Average percentcontrol dollar spot across all rating dates and locations.

Example 2. Turf Quality

Enhanced control of dollar spot with acibenzolar-S-methyl pluschlorothalonil was also apparent in turf quality ratings (Tables 6-7-).The lowest rate of Daconil Action, 1.3 fluid ounces, was numericallyequal to the 2.0, 1.82 and 1.58 fluid ounce rate of Quali-ProChlorothalonil 720 and significantly (P=0.10) superior to the 1.3 fluidounce rate. Applying acibenzolar-S-methyl in combination withchlorothalonil may allow for as much as a 30% rate reduction. This ratereduction will result in equal disease control with no loss in turfquality.

TABLE 6 Turf Quality Rating (1-9 Scale, 9 best) Across All RatingsWithin and Across All Trials 1-5. AVG Turf Quality/trial All ratings Oz/Trial Trial Trial Trial Trial 1000 1 2 3 4 5 Treatment sq. ft. PA* CT*MI* WI* NJ AVG** 1 Untreated 5.4 6.2 4.2 5.9 5.0 5.3 g Check 2 Daconil2.0  7.7 7.5 6.4 6.4 6.7 6.9 ab Action 3 Daconil 1.82 7.2 7.7 6.3 6.56.8 6.9 abc Action 4 Daconil 1.59 7.8 7.3 6.0 6.5 6.4 6.8 bcd Action 5Daconil 1.3  7.2 7.4 5.6 6.6 6.1 6.6 cde Action 6 Quali-Pro 2.0  7.1 7.26.0 6.5 6.3 6.6 b-e Chlorothalonil 7 Quali-Pro 1.82 7.4 6.7 5.7 6.5 6.16.5 def Chlorothalonil 8 Quali-Pro 1.59 6.8 7.7 5.2 6.4 6.2 6.5 efChlorothalonil 9 Quali-Pro 1.3  7.1 6.5 5.0 6.4 6.0 6.2 f Chlorothalonil*Average turf quality (1-9 scale) across all rating dates within trials.**Average turf quality (1-9 scale) across all rating dates andlocations. ***Means with same letter not different, LSD (P = 0.10)

TABLE 7 Turf Quality Rating (1-9 Scale, 9 best) Across All RatingsWithin and Across All Trials 6-8. AVG Turf Quality/trial All ratings Oz/Trial Trial Trial 1000 6 7 8 Treatment sq. ft. IN* CT* WI* AVG** 1Untreated Check 3.0 3.7 5.7 4.1e*** 2 Daconil Action 2.0 5.7 6.7 6.4 6.2a 3 Daconil Action 1.82 6.2 6.8 6.2 6.4 a 4 Daconil Action 1.59 5.7 5.86.3 6.0 ab 5 Daconil Action 1.3 5.1 5.5 6.1 5.6 bcd 6 Quali-ProChlorothalonil 2.0 5.4 5.7 5.6 5.6 bcd 7 Quali-Pro Chlorothalonil 1.825.1 6.0 6.3 5.8 bc 8 Quali-Pro Chlorothalonil 1.59 5.0 5.5 6.2 5.5 cd 9Quali-Pro Chlorothalonil 1.3 4.8 5.0 6.1 5.3 d *Average turf quality(1-9 scale) across all rating dates within trials. **Average turfquality (1-9 scale) across all rating dates and locations. ***Means withsame letter not different, LSD (P = 0.10)

These data support the claim that Daconil Action (acibenzolar-S-methylplus chlorothalonil) provides enhanced control of turf dollar spot(Sclerotinia homoeocarpa) over chlorothalonil applied alone. Applyingacibenzolar-S-methyl in combination with chlorothalonil may allow for asmuch as a 30% rate reduction without loss of disease control or turfquality.

Although the invention has been described with reference to preferredembodiments and examples thereof, the scope of the present invention isnot limited only to those described embodiments. As will be apparent topersons skilled in the art, modifications and adaptations to theabove-described invention can be made without departing from the spiritand scope of the invention, which is defined and circumscribed by theappended claims. All publications cited herein are hereby incorporatedby reference in their entirety for all purposes to the same extent as ifeach individual publication were specifically and individually indicatedto be so incorporated by reference.

The invention claimed is:
 1. A method for controlling or suppressingdollar spot in cool-season turfgrass, comprising applying to thecool-season turfgrass or to the locus of the cool-season turfgrass, afungicidally effective non-phytotoxic amount of a combination comprising(A) chlorothalonil and (B) acibenzolar-S-methyl, wherein (A) is appliedat a rate of from 2,000 to 10,000 g/ha and (B) is applied at a rate offrom 4 to 20 g/ha, wherein the combination of (A) and (B) is appliedpre-disease or under low to moderate dollar spot disease pressurepresent in the turfgrass.
 2. The method of claim 1, wherein the weightratio of chlorothalonil to acibenzolar-S-methyl is from 300:1 to 600:1.3. The method of claim 1, wherein chlorothalonil andacibenzolar-S-methyl are applied simultaneously together, separately, orin succession.
 4. The method of claim 1, wherein a fungicidallyeffective non-phytotoxic amount of a composition comprising a mixture ofchlorothalonil and acibenzolar-S-methyl is applied to the turfgrass orto the locus of the turfgrass.
 5. The method of claim 1, using acomposition comprising a combination of (A) and (B).
 6. The method ofclaim 5, wherein the composition of (A) and (B) further comprisesadjuvants, solvents, carrier, surfactants or extenders.
 7. The methodaccording to claim 6, wherein the composition comprises from 0.01 to 90%by weight of the combination of (A) and (B), from 10 to 99.99% of acarrier and from 0 to 20% of a surfactant.
 8. The method of claim 1,wherein chlorothalonil is applied at the rate of from 3000 to 10000g/ha.
 9. The method of claim 1, wherein acibenzolar-S-methyl is appliedat the rate of from 5 to 16 g/ha.
 10. The method of claim 1, wherein thecombined amount of chlorothalonil and acibenzolar-S-methyl that isapplied to the turfgrass or to the locus thereof is between about 3000to 5000 g/ha.
 11. The method according to claim 1, wherein thephytopathogenic disease is caused by one or more phytopathogenic fungiselected from the group consisting of Sclerotinia homeocarpa, Lanzia orMoillerodiscus spp.
 12. The method according to claim 1, wherein theturfgrass is an annual or perennial Gramineae belonging to at least oneof the genera Agropyron, Agrostis, Axonopus, Bromus, Buchloë, Cynodon,Eremochloa, Festuca, Lolium, Paspulum, Pennisetum, Phleum, Poa,Stenotaphrum or Zoysia.